Mitsubishi PLC programming to realize the reading time timer

Mitsubishi PLC (Programmable Logic Controller) is a device widely used in the field of industrial automation. It controls machines or production processes through programming. In many applications, time control is an important function, and the timer is a key component to achieve time control. This article will introduce in detail how to use Mitsubishi PLC programming to read out the time timer.

1. Basic concepts of timers

A timer is a device used to measure time intervals. It can implement functions such as delay and timing in PLC programs. In Mitsubishi PLC, timers are generally divided into two categories: T (basic timer) and D (data block timer).

1.1 Basic Timer (T)

The basic timer is the simplest type of timer, which uses a 16-bit counter to implement the timing function. The main features of the basic timer are as follows:

• Timing range: 0.1ms to 3276.7ms (for T0~T199).

• Timing accuracy: 0.1ms.

• Timer type: T0~T199.

1.2 Data Block Timer (D)

The block timer is a more advanced timer type that uses data blocks (such as D0, D1, etc.) to store timing values. The main features of the block timer are as follows:

• Timing range: 0.1ms to 3276.7s.

• Timing accuracy: 0.1ms.

• Timer type: D0~D7999.

2. Timer programming instructions

In Mitsubishi PLC, timer programming mainly uses the following instructions:

2.1 ST (Start Timing)

The ST instruction is used to start the timer. Its basic format is as follows:

ST T#time{ DPL}

• T#time: timer number and timing time.

• DPL: Data block timer number.

2.2 DT (Stop Timing)

The DT instruction is used to stop the timer. Its basic format is as follows:

DT T{ DPL}

• T: timer number.

• DPL: Data block timer number.

2.3 PLS (Pulse Output)

The PLS instruction is used to output a pulse signal. Its basic format is as follows:

PLS T#time Y

• T#time: timer number and pulse width.

• Y: Output relay.

3. Timer Programming Example

The following is a simple timer programming example to implement a delay control function.

3.1 Example Requirements

Suppose we need to control a motor so that it stops after a delay of 5 seconds after starting.

3.2 Programming steps

1. Define input and output: Assume the start button is X0, the stop button is X1, and the motor control relay is Y0.

2. Write startup logic:

// When the start button is pressed, start the timer
IF X0 THEN
ST T#5000
END_IF
END_IF

END_IF

1. Write the stop logic:

// When the stop button is pressed, stop the timer and turn off the motor
IF X1 THEN
DT T
Y0 := OFF
END_IF
END_IF

END_IF

1. Write delay control logic:

// When the timer reaches the set time, turn off the motor
IF T0 THEN
Y0 := OFF
END_IF
END_IF

END_IF

4. Advanced Application of Timer

In addition to basic delay control, timers can also be used for more complex applications, such as periodic control, time accumulation, etc.

4.1 Periodic Control

Periodic control is the repetition of an action at a certain time interval. This can be achieved by using two timers: one to control the execution of the action and the other to control the interval between the actions.

4.2 Time Accumulation

Time accumulation is the process of adding up time over multiple time periods. This can be achieved by using multiple timers and accumulators.

5. Notes

1. Timer number: Make sure timer numbers are not repeated.

2. Timer Type: Select the appropriate timer type according to your needs.

3. Timer accuracy: Be aware of the timer's accuracy limitations.

4. Timer overflow: For basic timers, pay attention to the overflow problem of the 16-bit counter.